This invention relates generally to a percussive, fluid-activated apparatus, and more particularly to a throttle valve system for a percussive, fluid-activated jackhammer. Typical throttle valve arrangements for jackhammers often consist of a single, rotary-type of valve. The clearance between the valve and surrounding housing demands extremely tight tolerances in order to prevent leakage past the valve. Leakage across the valve would result in uncontrolled operation of the tool. Such valves are relatively insensitive and nonresponsive to flow of fluid, and, therefore, do not provide the operator with good "feel" for best control of the tool.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
FIG. 3 is view, partially in cross section, with some parts shown in elevation, along A--A of FIG. 2.